This invention relates to a hydraulic system for controlling the weight transfer between the main frame and wing sections of an agricultural implement, such as a disk harrow.
One type of current disk harrow has a main frame and one or two wings which are attached pivotally (or hinged) with respect to the main frame. The main frame and the wings support gangs of disks which are drawn through the soil. In such disk harrows, the characteristic working or thrust force, due to implement-ground interaction, can create functional problems as soil conditions vary. These thrust forces act along the gang to create a moment about the hinge centerline of the wing which tends to pull the wing into the soil. Firm soils generate high thrust forces while loose soils generate relatively low forces. As a result, in firm soils, the wings may tend to penetrate deeper than the main frame while in loose soils, the wings tend to ride out. The result is unsatisfactory performance, i.e., ridging, incomplete cutout due to lack of penetration, etc. The weight balance between the wings and main frame is a delicate design parameter and is difficult to optimize for different wing sizes and soil conditions. Oftentimes, narrow wings tend to ride out and wide wings tend to penetrate too deeply, or vice versa. Currently, these problems are addressed by adding ballast to wing frames, by using compression springs in wingfold cylinders, and by using additional gang wheels on large wings. However, adjustment of ballast or of gauge wheels is inconvenient so that it is difficult to quickly adjust to changing soil conditions. Compression springs have a disadvantage in that the force they provide varies, depending upon the relative position between the main frame and the wing. Accordingly, some other more convenient system for adjusting disk harrow weight balance is desired.